JP2013222001A - Electrophotographic toner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrophotographic toner that has excellent low-temperature fixability and charge stability.SOLUTION: An electrophotographic toner includes, as a binder resin, core-shell particles in which a core part includes an amorphous resin (A) obtained through condensation polymerization of an alcohol component containing aliphatic diol having 2 to 6 carbon atoms and a carboxylic acid component not including alkenylsuccinic acid, and a shell part is an amorphous resin (B) obtained through condensation polymerization of an alcohol component and a carboxylic acid component including alkenylsuccinic acid. The content of alkenylsuccinic acid in the carboxylic acid component in the amorphous resin (B) is preferably 5 mol% or more.

Description

  The present invention relates to an electrophotographic toner and a method for producing the same.

Along with speeding up and energy saving of printing apparatuses, there is a demand for toners having excellent low-temperature fixability. Therefore, as a binder resin for toner, an aliphatic polyester using an aliphatic polyhydric alcohol has been proposed in place of an aromatic polyester obtained using an aromatic alcohol whose structure has been rigid. ing.
For example, in Patent Document 1, the softening point is 120 to 160 ° C. obtained by polycondensation of an alcohol component consisting essentially of an aliphatic alcohol and a carboxylic acid component for the purpose of improving fixability. For electrostatic image development, comprising a high softening point polyester and a low softening point polyester having a softening point of 75 to 120 ° C., wherein the difference in softening point between the high softening point polyester and the low softening point polyester is 10 ° C. or more. Toner is disclosed.
Patent Document 2 discloses composite resin particles in which resin fine particles (Q) containing a resin (q) are attached to the surface of resin particles (P) containing a resin (p) for the purpose of improving low-temperature fixability. Yes, (p) is formed by polycondensation of a polyol component and a polycarboxylic acid component, and the polyol component is composed of one or more polyester resins composed of 85 to 100 mol% of an aliphatic diol having 2 to 6 carbon atoms. The resin particle characterized by these is disclosed.
In Patent Document 3, a carbon component containing an alcohol component containing an aliphatic diol having 2 to 12 carbon atoms and an aliphatic dicarboxylic acid compound having 8 to 12 carbon atoms is used for the purpose of improving low-temperature fixability and charging rate. A crystalline polyester obtained by condensation polymerization of an acid component, at least one succinic acid compound selected from an alcohol component, an alkyl (carbon number 9 to 18) succinic acid, and an alkenyl (carbon number 9 to 18) succinic acid. An amorphous resin (A) obtained by polycondensation of the carboxylic acid component contained therein, and the shell portion of the carboxylic acid component and the alcohol component containing an aliphatic dialcohol having 2 to 5 carbon atoms. A binder resin for toner comprising core-shell particles, which is an amorphous resin (B) obtained by polymerization, is disclosed.

JP 2002-287427 A JP 2006-154686 A JP 2011-197193 A

Although the polycondensation-type resin obtained using aliphatic alcohol like patent documents 1-3 is excellent in low-temperature fixability, since it has high ester value, it is easy to absorb water under high temperature and high humidity, and high temperature and high humidity The charging stability at is insufficient. Further, if the ester value is lowered in order to improve the charging stability, the low-temperature fixability is inferior. Thus, it is difficult to obtain a binder resin for toner that is excellent in both low-temperature fixability and charging stability.
Further, as described above, Patent Document 3 discloses that alkyl succinic acid and alkenyl succinic acid are used as the carboxylic acid component of the amorphous resin (A) in the core part. Further, in Patent Document 3, as an effect of using the amorphous resin (A) in the core portion, the crystalline polyester in the core portion is finely dispersed in the amorphous resin (A) in the core portion. It is described that the transition to the shell portion is suppressed by staying in the core portion, the exposure of the crystalline polyester to the toner particle surface is reduced, and the low-temperature fixability and the charging rate of the toner can be improved. However, Patent Document 3 does not describe or suggest a technique of using alkyl succinic acid and alkenyl succinic acid as a carboxylic acid component of the amorphous resin (B) in the shell portion not containing a crystalline resin.

  An object of the present invention is to solve the above problems and provide an electrophotographic toner excellent in low-temperature fixability and charging stability and a method for producing the same.

  In the capsule type toner having a core part and a shell part, the present inventors use alkenyl succinic acid as the carboxylic acid component of the amorphous polyester in the shell part, and as the alcohol component of the amorphous polyester in the core part. It has been found that by using an aliphatic diol having 2 to 6 carbon atoms, an electrophotographic toner excellent in low-temperature fixability and charging stability can be obtained.

That is, the present invention relates to the following [1] to [2].
[1] The core portion includes an amorphous resin (A) obtained by polycondensation of an alcohol component containing an aliphatic diol having 2 to 6 carbon atoms and a carboxylic acid component not containing alkenyl succinic acid. An electrophotographic toner comprising a core-shell particle as a binder resin, wherein the part is an amorphous resin (B) obtained by condensation polymerization of an alcohol component and a carboxylic acid component containing alkenyl succinic acid.
[2] A method for producing an electrophotographic toner, comprising the following steps 1 to 4.
Step 1: Aggregating an aqueous resin dispersion containing an amorphous resin (A) obtained by condensation polymerization of an alcohol component containing an aliphatic diol having 2 to 6 carbon atoms and a carboxylic acid component not containing alkenyl succinic acid To obtain an aqueous dispersion of resin particles I Step 2: A resin aqueous dispersion containing an amorphous resin (B) obtained by condensation polymerization of an alcohol component and a carboxylic acid component containing alkenyl succinic acid Step 3: The aqueous dispersion of resin particles I obtained in Step 1 and the aqueous resin dispersion containing the amorphous resin (B) obtained in Step 2 are mixed and agglomerated to form resin particles II. Step of obtaining aqueous dispersion Step 4: Step of uniting resin particles II obtained in Step 3

  The photographic toner of the present invention is excellent in low-temperature fixability and charging stability.

The electrophotographic toner of the present invention includes an amorphous resin (A) obtained by condensation polymerization of an alcohol component containing a C 2-6 aliphatic diol and a carboxylic acid component, and the shell The portion contains core-shell particles as a binder resin, which is an amorphous resin (B) obtained by condensation polymerization of an alcohol component and a carboxylic acid component containing alkenyl succinic acid.
The photographic toner of the present invention is excellent in low-temperature fixability and charging stability. The reason is considered as follows.
In other words, by using hydrophobic alkenyl succinic acid as the carboxylic acid component of the amorphous polyester in the shell portion, the toner does not absorb water even under high temperature and high humidity, so that the charging stability of the toner is excellent. It is thought that it becomes. Further, by using an aliphatic diol having 2 to 6 carbon atoms as the alcohol component of the amorphous polyester in the core, the hydrophilicity of the core is increased due to the high ester value of the polyester, and the affinity with paper It is considered that the low-temperature fixability is improved. Furthermore, since amorphous polyester is used for both the core part and the shell part, the interface between the core part and the shell part is favorably bonded with an appropriate adhesive force. Since alkenyl succinic acid is introduced as the carboxylic acid component of the amorphous polyester of the part, the hydrophobicity becomes strong, and the core-shell structure is favorably maintained by moderately reducing the compatibility between the core part and the shell part, It is considered that an electrophotographic toner excellent in low-temperature fixability and charging stability can be obtained as a result of the functions of the core and shell being well expressed.

[Binder resin]
The binder resin for toner used in the present invention is composed of core-shell particles, the core portion includes the amorphous resin (A), and the shell portion is the amorphous resin (B). The core part preferably further contains crystalline polyester from the viewpoint of low-temperature fixability of the toner.

<Core part>
(Amorphous resin (A))
The amorphous resin (A) is obtained by polycondensing an alcohol component containing an aliphatic diol having 2 to 6 carbon atoms and a carboxylic acid component not containing alkenyl succinic acid.

[Alcohol component]
The alcohol component, which is a raw material monomer of the amorphous resin (A), contains an aliphatic diol having 2 to 6 carbon atoms from the viewpoint of improving the low-temperature fixability of the toner and the ester value of the resin. Examples of the aliphatic diol having 2 to 6 carbon atoms include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 1,2-pentanediol, 1,3-pentanediol, 1,4-pentanediol, 1,5-pentanediol, neopentyl glycol, 2,3-pentanediol, 2,4- Examples include pentanediol, 1,2-hexanediol, 1,3-hexanediol, 1,4-hexanediol, 1,5-hexanediol, 1,6-hexanediol, and the like. Among these, 2,3-butanediol, 1,2-propanediol and 1,6-hexanediol are preferable from the viewpoint of low-temperature fixability of the toner.
The content of the aliphatic diol having 2 to 6 carbon atoms is preferably 80 to 100 mol%, more preferably 90 to 100 mol%, and still more preferably 95 to 100 in the alcohol component from the viewpoint of low-temperature fixability of the toner. Mol%, and even more preferably substantially 100 mol%.

  The alcohol component of the present invention may contain an alcohol component other than the aliphatic diol having 2 to 6 carbon atoms to the extent that the effects of the present invention are not impaired. Examples of alcohol components other than aliphatic diols having 2 to 6 carbon atoms include aliphatic diols having 7 or more carbon atoms and trivalent or higher alcohols such as glycerin.

[Carboxylic acid component]
The carboxylic acid component which is a raw material monomer of the amorphous resin (A) is a carboxylic acid component which does not contain alkenyl succinic acid. As a result, the compatibility between the amorphous resin (A) and the amorphous resin (B) containing alkenyl succinic acid in the shell as a structural unit is moderately reduced, and low-temperature fixability and charging stability are improved. Can be made. The content of alkenyl succinic acid in the carboxylic acid component is preferably 1 mol% or less, more preferably 0.5 mol% or less, still more preferably 0.1 mol% or less, still more preferably 0.01 mol% or less, It is still more preferable that it is substantially 0 mol%. Examples of carboxylic acid components other than alkenyl succinic acid include dicarboxylic acid compounds other than alkenyl succinic acid and trivalent or higher polyvalent carboxylic acid compounds.

  Dicarboxylic acid compounds include oxalic acid, malonic acid, maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, succinic acid, adipic acid, sebacic acid, azelaic acid and other aliphatic dicarboxylic acids; phthalic acid, isophthalic acid And aromatic dicarboxylic acids such as terephthalic acid; alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid; and anhydrides and alkyl (C1 to C3) esters of these acids. Among these, aliphatic dicarboxylic acids and aromatic dicarboxylic acids are preferred, and aromatic dicarboxylic acid compounds are more preferred from the viewpoint of low-temperature fixability and charge stability of the toner. Specifically, fumaric acid, phthalic acid, isophthalic acid and terephthalic acid are preferable, phthalic acid, isophthalic acid and terephthalic acid are more preferable, and terephthalic acid is still more preferable. In the present invention, the above-mentioned acids, anhydrides of these acids, and alkyl esters of the acids are collectively referred to herein as carboxylic acid compounds.

  The carboxylic acid component preferably contains an aromatic dicarboxylic acid compound from the viewpoint of low-temperature fixability, chargeability, and heat-resistant storage stability of the toner. In the carboxylic acid component, the content of the aromatic dicarboxylic acid compound is preferably from 30 to 95 mol%, more preferably from 50 to 90 mol%, and still more preferably from 60 to 90 mol%, from the viewpoints of low-temperature fixability and charge stability of the toner. It is 85 mol%, More preferably, it is 80-85 mol%.

Examples of the trivalent or higher polyvalent carboxylic acid compounds include 1,2,4-benzenetricarboxylic acid (trimellitic acid), 2,5,7-naphthalenetricarboxylic acid, and aromatic carboxylic acids such as pyromellitic acid, and these Derivatives such as acid anhydrides and alkyl (C1-C3) esters can be mentioned.
Other carboxylic acid compounds include unpurified rosin, purified rosin, and rosin modified with fumaric acid, maleic acid, acrylic acid, and the like.

  In the present invention, the carboxylic acid component is a trivalent or higher polyvalent carboxylic acid compound, preferably a trimellitic acid compound, more preferably anhydrous, from the viewpoint of improving the heat resistant storage stability, high temperature offset resistance and charging stability of the toner. It is preferable to contain trimellitic acid. The content of the trivalent or higher polyvalent carboxylic acid compound is 0.1 to 30 in the carboxylic acid component from the viewpoint of increasing the molecular weight of the resin and improving the heat resistant storage stability, the high temperature offset resistance and the charging stability of the toner. Mol% is preferable, 1-25 mol% is more preferable, 5-25 mol% is still more preferable, and 15-20 mol% is still more preferable.

[Molar ratio of alcohol component to carboxylic acid component]
The molar ratio of the carboxylic acid component to the alcohol component (carboxylic acid component / alcohol component) is preferably 0.7 to 1.2, more preferably 0 from the viewpoint of improving the low-temperature fixability and charging stability of the toner. .75 to 1.1, more preferably 0.8 to 0.9.

(Crystalline polyester)
In the binder resin for toner used in the present invention, the core portion may further contain a crystalline polyester from the viewpoint of low-temperature fixability of the toner.
The kind of the alcohol component of the crystalline polyester is the same as the alcohol component of the amorphous resin (A). From the viewpoint of improving the crystallinity of the resin and improving the low-temperature fixability of the toner, 1,6-hexane is used. Diols are more preferred. The kind of the carboxylic acid component of the crystalline polyester is the same as the carboxylic acid component of the amorphous resin (A), and fumaric acid is more preferable from the viewpoint of improving the low-temperature fixability of the toner.
In the present invention, the crystalline polyester means that the ratio of the softening point to the maximum endothermic peak temperature (softening point (° C.) / Maximum endothermic peak temperature (° C.)) in the measurement method described in the examples described later is 0. It refers to a resin that is 6 to 1.3, preferably 0.9 to 1.2, and more preferably 1.0 to 1.2.
Amorphous resin refers to a resin having a ratio of softening point to endothermic maximum peak temperature (softening point (° C.) / Endothermic maximum peak temperature (° C.)) of greater than 1.3 or less than 0.6. , Preferably greater than 1.3 and 4 or less, more preferably 1.5-3.

[Physical properties of crystalline polyester]
The number average molecular weight of the crystalline polyester used in the present invention is not particularly limited, but from the viewpoint of improving the low-temperature fixability of the toner and improving the heat-resistant storage stability and high-temperature offset resistance of the toner, 1 1,000 to 6,000 are preferred, 1,000 to 5,000 are more preferred, and 1,500 to 4,500 are even more preferred.
The weight average molecular weight of the crystalline polyester used in the present invention is 3,000 to 100,000 from the viewpoint of improving the low-temperature fixability of the toner and the heat-resistant storage stability and high-temperature offset resistance of the toner. Preferably, 5,000-50,000 are more preferable, 5,000-30,000 are still more preferable, and 7,000-20,000 are still more preferable.
In the present invention, the number average molecular weight and the weight average molecular weight of the crystalline polyester are both values obtained by measuring the chloroform-soluble content.

The softening point of the crystalline polyester used in the present invention is preferably 60 to 160 ° C., more preferably 80 to 140 ° C., more preferably 100 to 100 ° C. from the viewpoints of low-temperature fixability, heat-resistant storage stability and high-temperature offset resistance of the toner. 120 degreeC is still more preferable and 110-120 degreeC is still more preferable.
The melting point of the crystalline polyester used in the present invention is preferably 60 to 150 ° C., more preferably 80 to 130 ° C., and still more preferably 100 from the viewpoints of toner low-temperature fixability, chargeability, environmental stability, and heat-resistant storage stability. It is -120 degreeC, More preferably, it is 105-115 degreeC.
The acid value of the crystalline polyester is preferably 1 to 40 mgKOH / g, and preferably 2 to 35 mgKOH from the viewpoint of improving the dispersion of the crystalline polyester in the aqueous dispersion and the low-temperature fixability and charging stability of the toner. / G is more preferable, 3 to 30 mgKOH / g is more preferable, and 15 to 25 mgKOH / g is still more preferable.
The number average molecular weight, softening point, melting point, and acid value can be easily adjusted by adjusting the raw material monomer composition, the polymerization initiator, the molecular weight, the catalyst amount, etc., or by selecting the reaction conditions.

(Modified amorphous resin)
The amorphous resin (A) used in the present invention may contain a modified amorphous resin.
Examples of the modified amorphous resin include a urethane-modified polyester in which the resin is modified with a urethane bond, an epoxy-modified polyester in which the polyester is modified with an epoxy bond, and a hybrid resin having two or more resins including a polyester component. Can be mentioned.

(Release agent)
You may contain a mold release agent in the core part of a core-shell particle.
When a release agent is used, the weight ratio of the release agent to the total binder resin including the amorphous resin (A) in the core portion [release agent / total binder resin including the amorphous resin (A)] is From the viewpoint of low-temperature fixability, heat-resistant storage stability, and high-temperature offset resistance of the toner, 0.1 / 100 to 10/100 is preferable, 0.5 / 100 to 5/100 is more preferable, and 1/100 to 3/100 is preferable. 100 is more preferable.
The weight ratio of the release agent to the amorphous resin [(A) + (B)] in the core-shell particles [release agent / amorphous resin [(A) + (B)]] is the low-temperature fixability of the toner, From the viewpoint of heat resistant storage stability and high temperature offset resistance, 0.1 / 100 to 10/100 is preferable, 0.5 / 100 to 5/100 is more preferable, and 1/100 to 2/100 is still more preferable.
As release agents, low molecular weight polyolefins such as polyethylene, polypropylene and polybutene; silicones having a softening point upon heating; fatty acid amides such as oleic acid amide, erucic acid amide, ricinoleic acid amide, and stearic acid amide; Plant waxes such as uba wax, rice wax, candelilla wax, tree wax and jojoba oil; animal waxes such as beeswax; minerals such as montan wax, paraffin wax, ozokerite, ceresin, microcrystalline wax, and Fischer-Tropsch wax Examples include petroleum wax. Among these, paraffin wax is preferable from the viewpoint of availability. These mold release agents can be used alone or in combination of two or more.
The release agent is preferably used as a release agent particle dispersion liquid dispersed in an aqueous medium from the viewpoint of dispersibility and cohesiveness with resin particles.

<Shell part>
(Amorphous resin (B))
The amorphous resin (B) is obtained by polycondensing an alcohol component and a carboxylic acid component containing alkenyl succinic acid.

[Alcohol component]
From the viewpoint of increasing the ester value, the alcohol component that is a raw material monomer of the amorphous resin (B) preferably contains an aliphatic diol, and more preferably contains an aliphatic diol having 2 to 6 carbon atoms. The aliphatic diol having 2 to 6 carbon atoms is the same as the amorphous resin (A), and 2,3-butanediol, 1,2-propanediol, neodymium is used from the viewpoint of low-temperature fixability and charging stability of the toner. Pentyl glycol, ethylene glycol and 1,6-hexanediol are preferred.

  When an aliphatic diol having 2 to 6 carbon atoms is used as the alcohol component of the present invention, the content of the aliphatic diol having 2 to 6 carbon atoms is selected from the viewpoints of low-temperature fixability and charge stability of the toner. Preferably it is 80-100 mol%, More preferably, it is 90-100 mol%, More preferably, it is 95-100 mol%.

  Examples of the alcohol component other than the aliphatic diol having 2 to 6 carbon atoms include an alkylene diol of bisphenol A represented by the following (1), in addition to an aliphatic diol having 7 or more carbon atoms and a trivalent or higher alcohol such as glycerin. From the viewpoint of environmental stability and heat resistant storage stability of the toner, an alkylene oxide adduct of bisphenol A represented by the following (1) is preferable.

（式中、ＲＯ及びＯＲはオキシアルキレン基であり、Ｒはエチレン及び／又はプロピレン基であり、ｘ及びｙはアルキレンオキサイドの付加モル数を示し、それぞれ正の数であり、ｘとｙの和の平均値は１〜１６が好ましく、１〜８がより好ましく、１．５〜４が更に好ましい。）

(In the formula, RO and OR are oxyalkylene groups, R is an ethylene and / or propylene group, x and y indicate the number of added moles of alkylene oxide, each being a positive number, and the sum of x and y. 1-16 are preferable, 1-8 are more preferable, and 1.5-4 are still more preferable.

  Specific examples of the alkylene oxide adduct of bisphenol A represented by the formula (I) include 2,2-bis (4-hydroxyphenyl) propane polyoxypropylene adduct and 2,2-bis (4- And an alkylene oxide adduct of bisphenol A such as a polyoxyethylene adduct of hydroxyphenyl) propane.

  In the case of using the alkylene oxide adduct of bisphenol A, the content of the alkylene oxide adduct of bisphenol A is more preferably 80 to 100 mol% in the alcohol component from the viewpoint of environmental stability and heat-resistant storage stability of the toner. Is 90 to 100 mol%, more preferably 95 to 100 mol%.

[Carboxylic acid component]
The carboxylic acid component which is a raw material monomer of the amorphous resin (B) includes alkenyl succinic acid. Since the alkenyl succinic acid is hydrophobic, the toner does not absorb water even under high temperature and high humidity, and the toner has excellent charge stability. The alkenyl succinic acid of the present invention includes alkenyl succinic anhydride.

《Alkenyl succinic acid》
The carbon number of the alkenyl group in the alkenyl succinic acid is preferably 9-18, more preferably 9-14, and still more preferably 10-12, from the viewpoint of low-temperature fixability and charging stability of the toner.
These alkenyl groups may be linear or branched, but are preferably branched from the viewpoint of low-temperature fixability and charge stability of the toner.
Further, from the viewpoint of low-temperature fixability and charge stability of the toner, the alkenyl succinic acid is preferably composed of two or more types. The “kind” referred to here is derived from an alkenyl group, and alkenyl groups having different carbon chain lengths and structural isomers are treated as different types of alkenyl succinic acid.

Accordingly, the alkenyl succinic acid is preferably an alkenyl having a branched alkenyl group having 9 to 18 carbon atoms, more preferably 9 to 14 carbon atoms, and still more preferably 10 to 12 carbon atoms from the viewpoint of low-temperature fixability and charge stability of the toner. What consists of 2 or more types of succinic acid is preferable. By using together alkenyl succinic acid having a branched alkenyl group having a different carbon number, the obtained resin has a broad endothermic peak near the glass transition point in differential scanning calorimetry (DSC), and the binder resin for toner. As a result, it has a very wide fixing temperature range.
Specific examples of the alkenyl group having 9 to 18 carbon atoms having a branched chain include an isododecenyl group.

  From the viewpoint of low-temperature fixability, charge stability, and heat-resistant storage stability of the toner, the alkenyl succinic acid is at least one selected from a compound having an alkylene group (alkylene compound), maleic acid, fumaric acid and acid anhydrides thereof. It is preferable that it is obtained from these.

  As the alkylene compound, those having 9 to 18 carbon atoms, preferably 9 to 14 carbon atoms, more preferably 10 to 12 carbon atoms are preferable from the viewpoint of low-temperature fixability and charge stability of the toner. Those obtained from isobutylene, normal butylene and the like, for example, trimers and tetramers thereof are preferably used. As a suitable raw material used for the synthesis of the alkylene compound, propylene having a low molecular weight is preferable from the viewpoint of increasing the number of structural isomers. In addition, the alkylene compound is a polycondensation resin obtained by using alkenyl succinic acid, as a binder resin for toner, and has a very wide fixing temperature range. And preferably having 2 or more peaks corresponding to an alkylene compound having 9 to 18 carbon atoms, preferably 9 to 14 carbon atoms, more preferably 10 or more, still more preferably 20 or more, still more preferably 30 or more, and 80 The following is preferable, and 60 or less is more preferable.

  The content of alkenyl succinic acid is preferably 5 mol% or more, preferably 5 to 60 mol%, more preferably 5 to 55 mol% in the carboxylic acid component, from the viewpoint of low-temperature fixability and charge stability of the toner. 10-50 mol% is still more preferable, 20-45 mol% is still more preferable, and 30-40 mol% is still more preferable.

<< Method for Producing Alkenyl Succinic Acid >>

The alkenyl succinic acid can be obtained by an arbitrary production method. For example, an alkylene compound and at least one selected from maleic acid, fumaric acid and acid anhydrides thereof are mixed and heated to obtain an ene succinic acid. It can be obtained by utilizing a reaction (see JP-A-48-23405, JP-A-48-23404, US Pat. No. 3,374,285, etc.).
Among maleic acid, fumaric acid and acid anhydrides thereof, maleic anhydride is preferable from the viewpoint of reactivity.
Suitable catalysts used for the synthesis of the alkylene compound include liquid phosphoric acid, solid phosphoric acid, tungsten, boron trifluoride complex and the like. From the viewpoint of ease of control of the number of structural isomers, a method of adjusting by distillation after random polymerization is preferred.

<< Carboxylic acid components other than alkenyl succinic acid >>
In addition to the alkenyl succinic acid, the carboxylic acid component may contain one or more of succinic acid, alkyl succinic acid, other dicarboxylic acid compounds, and trivalent or higher polyvalent carboxylic acid compounds.
The number of carbon atoms of the alkyl group of the alkyl succinic acid and the presence or absence of branching are the same as those of the alkenyl group of the alkenyl succinic acid, and isododecyl group is preferable.

  Other dicarboxylic acid compounds include oxalic acid, malonic acid, maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, succinic acid, adipic acid, sebacic acid, azelaic acid and other aliphatic dicarboxylic acids; phthalic acid, Examples thereof include aromatic dicarboxylic acids such as isophthalic acid and terephthalic acid; alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid; and anhydrides and alkyl (C1 to C3) esters of these acids. Among these, aliphatic dicarboxylic acids and aromatic dicarboxylic acids are preferable from the viewpoint of low-temperature fixability and charging stability of the toner, and it is more preferable to contain an aromatic dicarboxylic acid compound. Specifically, from the same viewpoint, fumaric acid, phthalic acid, isophthalic acid and terephthalic acid are preferable, and fumaric acid, isophthalic acid and terephthalic acid are more preferable. In the present invention, the above-mentioned acids, anhydrides of these acids, and alkyl esters of the acids are collectively referred to herein as carboxylic acid compounds.

  The carboxylic acid component preferably contains an aromatic dicarboxylic acid compound from the viewpoint of low-temperature stability, charging stability, and heat-resistant storage stability of the toner. In the carboxylic acid component, the content of the aromatic dicarboxylic acid compound is preferably 30 to 90 mol%, more preferably 35 to 80 mol%, and still more preferably 40 to 70, from the viewpoint of chargeability and heat-resistant storage stability of the toner. It is mol%, More preferably, it is 45-65 mol%.

Examples of the trivalent or higher polyvalent carboxylic acid compounds include 1,2,4-benzenetricarboxylic acid (trimellitic acid), 2,5,7-naphthalenetricarboxylic acid, and aromatic carboxylic acids such as pyromellitic acid, and these Derivatives such as acid anhydrides and alkyl (C1-C3) esters can be mentioned.
Other carboxylic acid compounds include unpurified rosin, purified rosin and rosin modified with fumaric acid, maleic acid, acrylic acid, and the like.

  In the present invention, the carboxylic acid component contains a trivalent or higher polyvalent carboxylic acid compound, preferably a trimellitic acid compound, more preferably trimellitic anhydride, from the viewpoint of improving the charging stability and heat-resistant storage stability of the toner. It is preferable. The content of the trivalent or higher polyvalent carboxylic acid compound is preferably from 0.1 to 30 mol%, and preferably from 1 to 25 mol%, in the carboxylic acid component, from the viewpoint of improving the charging stability and heat resistant storage stability of the toner. More preferably, 5-25 mol% is still more preferable.

[Physical properties of amorphous resins (A) and (B)]
The number average molecular weights of the amorphous resins (A) and (B) are each preferably from 1,000 to 6,000, from the viewpoints of low-temperature fixability, heat-resistant storage stability, and high-temperature offset resistance of the toner. 1,000 to 5,000 is more preferable, and 2,000 to 4,000 is still more preferable. The weight average molecular weights of the amorphous resins (A) and (B) are preferably independently from 2,000 to 500,000 from the viewpoints of low-temperature fixability, heat-resistant storage stability and high-temperature offset resistance of the toner. More preferably, it is 3,000-100,000, More preferably, it is 5,000-50,000, More preferably, it is 5,000-40,000. The number average molecular weight and the weight average molecular weight of the amorphous resin are both values obtained by measuring the tetrahydrofuran soluble content.

The softening points of the amorphous resins (A) and (B) are each independently preferably from 70 to 180 ° C., more preferably from 90 to 180 ° C., from the viewpoints of low temperature fixability, heat resistant storage stability and high temperature offset resistance of the toner. It is 150 degreeC, More preferably, it is 95-130 degreeC.
In general, when core-shell particles are used, in order to encapsulate the release agent in the core part, the softening point of the amorphous resin in the shell part is often increased. On the other hand, in the present invention, since a specific resin is used for the core part and the shell part, the softening point of the amorphous resin (B) in the shell part is set to the softening point (A ), The release agent can be confined in the core portion, thereby improving the low-temperature fixability of the toner.
From the above viewpoint, when the softening point of the amorphous resin (B) in the shell portion is set lower than the softening point (A) of the amorphous resin in the core portion, from the viewpoint of low-temperature fixability of the toner, Preferably it is 1 ° C. or higher, more preferably 2 ° C. or higher, more preferably 3 ° C. or lower, and the upper limit is preferably 50 ° C. or lower, more preferably 30 ° C. or lower, and even more preferably 10 ° C. or lower.

The glass transition temperatures (Tg) of the amorphous resins (A) and (B) are each independently preferably from 35 to 80 ° C. from the viewpoint of low-temperature fixability, heat-resistant storage stability and high-temperature offset resistance of the toner. Preferably it is 40-75 degreeC, More preferably, it is 40-70 degreeC, More preferably, it is 42-65 degreeC.
The acid value of the amorphous resins (A) and (B) is preferably 1 to 70 mgKOH / g independently from the viewpoint of improving the dispersion of the amorphous resin in the aqueous dispersion. 60 mgKOH / g is more preferable, 20-50 mgKOH / g is still more preferable, and 20-30 mgKOH / g is still more preferable.
The number average molecular weight, softening point, Tg, and acid value can be easily adjusted by adjusting the raw material monomer composition, the polymerization initiator, the molecular weight, the catalyst amount, etc., or by selecting the reaction conditions.

<Production method of polyester resin>
There is no restriction | limiting in particular in the manufacturing method of a polyester-type resin, Although it can manufacture by a well-known method, a polyester-type resin is obtained by the condensation polymerization reaction of an alcohol component and a carboxylic acid component. The polycondensation reaction is preferably performed in the presence of an esterification catalyst, and is more preferably performed in the presence of an esterification catalyst and a pyrogallol compound from the viewpoints of reactivity, molecular weight adjustment, and resin physical property adjustment.
Here, examples of the polyester resin include the aforementioned amorphous resin (A), crystalline polyester, modified amorphous resin, and amorphous resin (B).

<Esterification catalyst>
Examples of the esterification catalyst suitably used for the condensation polymerization include a titanium compound and a tin (II) compound having no Sn-C bond, and these may be used alone or in combination of two or more. it can.

  As a titanium compound, the titanium compound which has a Ti-O bond is preferable, and the compound which has a C1-28 total carbon number alkoxy group, an alkenyloxy group, or an acyloxy group is more preferable.

  Examples of the tin (II) compound having no Sn—C bond include a tin (II) compound having a Sn—O bond, a tin (II) compound having a Sn—X (X represents a halogen atom) bond, and the like. Preferred is a tin (II) compound having a Sn-O bond, and among them, a dioctylic acid tin (II) salt is more preferable from the viewpoints of reactivity, molecular weight adjustment, and resin physical property adjustment.

  The amount of the esterification catalyst is preferably 0.01 to 1 part by weight with respect to 100 parts by weight of the total amount of the alcohol component and the carboxylic acid component, from the viewpoints of reactivity, molecular weight adjustment, and resin physical property adjustment. More preferably, it is 1 to 0.6 parts by weight.

<Pyrogallol compound>
A pyrogallol compound has a benzene ring in which three hydrogen atoms adjacent to each other are substituted with a hydroxyl group, and pyrogallol, gallic acid, gallic acid ester, 2,3,4-trihydroxybenzophenone, 2,2 ′, Examples include benzophenone derivatives such as 3,4-tetrahydroxybenzophenone, catechin derivatives such as epigallocatechin and epigallocatechin gallate, and gallic acid is preferred from the viewpoint of reactivity.
The abundance of the pyrogallol compound in the condensation polymerization reaction is preferably 0.001 to 1 part by weight with respect to 100 parts by weight of the total amount of the alcohol component and the carboxylic acid component subjected to the condensation polymerization reaction, from the viewpoint of reactivity. 0.005-0.4 weight part is more preferable, and 0.01-0.2 weight part is still more preferable. Here, the abundance of the pyrogallol compound means the total amount of the pyrogallol compound subjected to the condensation polymerization reaction.
From the viewpoint of reactivity, the weight ratio of the pyrogallol compound to the esterification catalyst (pyrogallol compound / esterification catalyst) is preferably 0.01 to 0.5, more preferably 0.02 to 0.3, and 0.03. -0.2 is still more preferable.

The polycondensation reaction between the alcohol component and the carboxylic acid component can be performed, for example, in the presence of the esterification catalyst in an inert gas atmosphere at a temperature of 120 to 250 ° C, preferably 140 to 240 ° C.
In addition, for example, all monomers are charged together to increase the strength of the resin, or divalent monomers are first reacted to reduce low molecular weight components, and then trivalent or higher monomers are added and reacted. A method may be used. Further, the reaction may be accelerated by reducing the pressure of the reaction system in the latter half of the polymerization.

(Binder resin for toner)
The binder resin for toner used in the present invention comprises core-shell particles.
The weight ratio of the amorphous resin (B) to 100 parts by weight of the total binder resin including the amorphous resin (A) is preferably 10 to 120 parts by weight from the viewpoint of low-temperature fixability and charging stability of the toner. 20-100 weight part is more preferable, 20-70 weight part is still more preferable, and 30-60 weight part is still more preferable.

  The weight ratio of the amorphous resin (B) to 100 parts by weight of the amorphous resin (A) is preferably 10 to 120 parts by weight from the viewpoint of low-temperature fixability and charging stability of the toner. Part is more preferable, 20-70 weight part is still more preferable, and 30-60 weight part is still more preferable.

The weight ratio when crystalline polyester is used for the core is as follows.
The weight ratio of the crystalline polyester to the amorphous resin (A) in the core part [crystalline polyester / amorphous resin (A)] is 5/95 to 40 from the viewpoint of low-temperature fixability and charging stability of the toner. / 60 is preferable, 8/92 to 30/70 is more preferable, 10/90 to 25/75 is still more preferable, and 10/90 to 20/80 is still more preferable.

  The weight ratio [crystalline polyester / amorphous resin [(A) + (B)]] of the crystalline polyester to the amorphous resin [(A) + (B)] in the core-shell particles is the low-temperature fixability of the toner, From the viewpoint of chargeability, environmental stability and heat-resistant storage stability, 5/95 to 40/60 is preferable, 6/94 to 25/75 is more preferable, 8/92 to 20/80 is still more preferable, and 10/90 to 15/85 is even more preferable.

[Electrophotographic toner]
The electrophotographic toner of the present invention containing the binder resin is a known toner binder resin different from the binder resin, for example, polyester, styrene-acrylic resin, etc., as long as the effects of the present invention are not impaired. The styrenic resin, epoxy resin, polycarbonate, polyurethane and the like may be contained in the core part or the shell part.
In the toner for electrophotography of the present invention, the content of the binder resin for toner of the present invention is preferably 50% by weight or more based on the total binder resin from the viewpoint of low-temperature fixability and charge stability of the toner. % By weight or more is more preferable, 80% by weight or more is more preferable, 90% by weight or more is further preferable, and substantially 100% by weight is still more preferable.

[Method for producing toner for electrophotography]
The toner for electrophotography of the present invention can be produced by a production method including the following steps 1 to 4.
Step 1: Aggregating an aqueous resin dispersion containing an amorphous resin (A) obtained by condensation polymerization of an alcohol component containing an aliphatic diol having 2 to 6 carbon atoms and a carboxylic acid component not containing alkenyl succinic acid And obtaining an aqueous dispersion of resin particles I.
Step 2: A step of obtaining a resin aqueous dispersion containing an amorphous resin (B) obtained by condensation polymerization of an alcohol component and a carboxylic acid component containing alkenyl succinic acid.
Step 3: The aqueous dispersion of core-forming resin particles I obtained in Step 1 and the aqueous resin dispersion containing the amorphous resin (B) obtained in Step 2 are mixed and agglomerated to obtain resin particles II. A step of obtaining an aqueous dispersion liquid.
Step 4: A step of uniting the resin particles II obtained in Step 3.
An electrophotographic toner comprising core-shell particles as a binder resin, wherein the core portion contains an amorphous resin (A) and the shell portion is an amorphous resin (B). A toner containing a release agent can be produced.

<Step 1>
Step 1 is an aqueous resin dispersion containing an amorphous resin (A) obtained by condensation polymerization of an alcohol component containing an aliphatic diol having 2 to 6 carbon atoms and a carboxylic acid component not containing alkenyl succinic acid. In this step, an aqueous dispersion of a release agent and / or an aqueous dispersion of crystalline polyester are mixed as necessary, and then aggregated to obtain an aqueous dispersion of resin particles I.
In the present specification, “aqueous” may contain a solvent such as an organic solvent, but water is preferably 50% by weight or more, preferably 70% by weight or more, more preferably 90% by weight or more. Preferably it contains 99% by weight or more. Further, hereinafter, when simply described as “resin”, it refers to both crystalline polyester and amorphous resin.

(Preparation of resin aqueous dispersion containing amorphous resin (A))
[Preparation using organic solvent]
A resin aqueous dispersion containing the amorphous resin (A) is prepared by mixing the amorphous resin (A), an organic solvent and water, and further, if necessary, a neutralizing agent and a surfactant, stirring, distillation, etc. Is obtained by removing the organic solvent. Preferably, the amorphous resin (A) and, if necessary, the surfactant are dissolved in an organic solvent, and then water and, if necessary, a neutralizing agent are mixed. In addition, when stirring a mixture, arbitrary mixing stirring apparatuses, such as an anchor wing | blade, can be used.

Examples of the organic solvent include alcohol solvents such as ethanol, isopropanol and isobutanol; ketone solvents such as acetone, 2-butanone, methyl ethyl ketone, methyl isobutyl ketone and diethyl ketone; ether solvents such as dibutyl ether, tetrahydrofuran and dioxane; acetic acid Ethyl is mentioned. Among these, methyl ethyl ketone, ethyl acetate, and 2-butanone are preferable from the viewpoint of dispersibility of the binder resin, and methyl ethyl ketone is more preferable.
Examples of the neutralizing agent include alkali metals such as lithium hydroxide, sodium hydroxide and potassium hydroxide; organic bases such as ammonia, trimethylamine, ethylamine, diethylamine, triethylamine, triethanolamine and tributylamine. From the viewpoint of workability, sodium hydroxide is preferable.
Examples of the surfactant include anionic surfactants such as sulfate ester, sulfonate, phosphate, and soap (such as alkyl ether carboxylate); amine salt type and quaternary ammonium salt Type cationic surfactants; polyoxyethylene alkyl aryl ethers such as polyoxyethylene nonylphenyl ether, polyoxyethylene alkyl ethers such as polyoxyethylene oleyl ether and polyoxyethylene lauryl ether, polyoxyethylene sorbitan mono Polyoxyethylene sorbitan esters such as laurate and polyoxyethylene sorbitan monostearate, polyethylene glycol monolaurate, polyethylene glycol monostearate and polyethylene glycol monoole Polyoxyethylene fatty acid esters over preparative like, nonionic surfactants such as polyoxyethylene / polyoxypropylene block copolymers, and the like. When a surfactant is used, the amount used is preferably 0.1 to 20 with respect to 100 parts by weight of the total binder resin including the amorphous resin (A) from the viewpoint of dispersibility of the binder resin. Part by weight, more preferably 0.5 to 10 parts by weight.

The amount of the organic solvent mixed with the binder resin containing the amorphous resin (A) is 100 parts by weight of the total binder resin containing the amorphous resin (A) from the viewpoint of solubility of the binder resin. 100-1000 weight part is preferable and 150-500 weight part is more preferable. The amount of water to be mixed with the binder resin containing the amorphous resin (A) is preferably 100 to 1000 parts by weight with respect to 100 parts by weight of the organic solvent from the viewpoint of dispersibility of the binder resin, More preferred is 500 parts by weight.
The temperature at which the amorphous resin (A) and the organic solvent are mixed is preferably 30 to 90 ° C, more preferably 40 to 80 ° C, from the viewpoint of the solubility of the binder resin.
The solid content concentration of the aqueous dispersion of the amorphous resin (A) is preferably 3 to 50% by weight, more preferably 5 to 30% by weight, from the viewpoint of dispersibility of the binder resin, by appropriately adding water. More preferably, it is adjusted to 7 to 15% by weight.

(Volume median particle size)
The volume median particle size of the binder resin particles containing the amorphous resin (A) in the aqueous dispersion is preferably 50 to 1,000 nm from the viewpoint of uniform aggregation in the subsequent aggregation step. -500 nm is more preferable, 50-400 nm is still more preferable, and 100-350 nm is still more preferable. The volume-median particle size can be measured by a laser diffraction type particle size measuring device described later.

(Preparation of aqueous resin dispersion containing crystalline polyester)
The aqueous resin dispersion containing the crystalline polyester can also be produced in the same manner as the aqueous resin dispersion containing the amorphous resin (A), and the preferred range is also the same.

(Preparation of aqueous dispersion of resin particles I (aggregation step))
Next, if necessary, the resin aqueous dispersion containing the amorphous resin (A) and the aqueous dispersion of the release agent and / or the resin aqueous dispersion containing the crystalline polyester are mixed, and then aggregated. An aqueous dispersion of resin particles I is obtained.
In addition, the resin aqueous dispersion containing the amorphous resin (A) is further added with, for example, a colorant, a charge control agent, a conductivity adjusting agent, an extender pigment, a reinforcing filler such as a fibrous substance, an antioxidant, and You may make it aggregate after adding additives, such as anti-aging agent. The additive can also be used as an aqueous dispersion.
Further, in the aggregating step, an aggregating agent can be added in order to effectively agglomerate.
〔Release agent〕
The addition amount of the release agent is 0.1 from the viewpoint of dispersibility in the resin with respect to 100 parts by weight of the total amount of the binder resin including the amorphous resin (A), which is the core-forming resin particles. -10 parts by weight is preferred, 0.5-10 parts by weight is more preferred, 0.5-5 parts by weight is still more preferred, and 1-3 parts by weight is even more preferred. The weight ratio of the release agent and the amorphous resin (A) in the core is as described above.

[Colorant]
There is no restriction | limiting in particular as a coloring agent, A well-known coloring agent is mentioned, According to the objective, it can select suitably. Specifically, carbon black, inorganic composite oxide, chrome yellow, hansa yellow, benzidine yellow, selenium yellow, quinoline yellow, permanent orange GTR, pyrazolone orange, vulcan orange, watch young red, permanent red, brilliantamine 3B, Brilliantamine 6B, DuPont Oil Red, Pyrazolone Red, Resol Red, Rhodamine B Lake, Lake Red C, Bengal, Aniline Blue, Ultramarine Blue, Calco Oil Blue, Methylene Blue Chloride, Phthalocyanine Blue (Copper Phthalocyanine), Phthalocyanine Green, and Malachite Various pigments such as green oxalate; acridine, xanthene, azo, benzoquinone, azine, anthraquino System, indigo, thioindigo, phthalocyanine, aniline black, polymethine, triphenylmethane dyes, diphenylmethane dyes, thiazine, and include various dyes of thiazole, and the like. These can be used alone or in combination of two or more. In the case of adding a colorant, the amount added is from the viewpoint of improving the image quality with respect to 100 parts by weight of the total amount of the binder resin including the amorphous resin (A) as the core-forming resin particles. 1-20 weight part is preferable, 1-10 weight part is more preferable, and 5-10 weight part is still more preferable.

[Charge control agent]
Examples of the charge control agent include chromium-based azo dyes, iron-based azo dyes, aluminum azo dyes, and salicylic acid metal complexes. Salicylic acid metal complexes are preferable from the viewpoint of charging stability and availability of toner. Various charge control agents may be used alone or in combination of two or more. When the charge control agent is added, the addition amount is 0 with respect to 100 parts by weight of the total amount of the binder resin including the amorphous resin (A), which is the core-forming resin particle, from the viewpoint of improving the image quality. 0.1-8 parts by weight is preferred, 0.3-7 parts by weight is more preferred, and 0.8-3 parts by weight is even more preferred.

(Crystalline polyester)
A preferable mixing weight ratio between the crystalline polyester and the amorphous resin (A) is the same as the weight ratio shown in the above description regarding the binder resin for toner.

[Flocculant]
As the aggregating agent, a quaternary ammonium salt cationic surfactant, polyethyleneimine, or the like is used in the organic system, and an inorganic metal salt, an inorganic ammonium salt, a divalent or higher metal complex, or the like is used in the inorganic system. .
Examples of the inorganic metal salt include metal salts such as sodium sulfate, sodium chloride, calcium chloride, calcium nitrate, barium chloride, magnesium chloride, zinc chloride, aluminum chloride, and aluminum sulfate; polyaluminum chloride, polyaluminum hydroxide, and Examples thereof include inorganic metal salt polymers such as calcium polysulfide. Examples of the inorganic ammonium salt include ammonium sulfate, ammonium chloride, and ammonium nitrate.
When the flocculant is added, the addition amount is preferably 60 parts by weight or less, more preferably 30 parts by weight or less, and more preferably 10 parts by weight or less with respect to 100 parts by weight of the binder resin from the viewpoint of environmental resistance characteristics of the toner. Is more preferable.
In order to cause uniform agglomeration, the flocculant is preferably added after being dissolved in an aqueous medium, and is preferably sufficiently stirred at the time of addition of the flocculant and after completion of the addition.

[Conditions in the system]
In the aggregation step, the solid content concentration in the system is preferably 5 to 50% by weight, more preferably 5 to 30% by weight, and still more preferably 5 to 20% by weight in order to cause uniform aggregation.

The pH in the system in the aggregation step is preferably 2 to 10, more preferably 2 to 9, and still more preferably 3 to 8, from the viewpoint of achieving both the dispersion stability of the mixed solution and the aggregation property of the resin particles.
From the same viewpoint, the temperature in the system in the coagulation step is equal to or higher than the “softening point of the binder resin in the core portion—75 ° C.” (temperature lower by 75 ° C. than the softening point, the same shall apply hereinafter) and the binder resin in the core portion. It is preferable that it is below the softening point. In the present invention, since the amorphous resin (A) is used as the binder resin of the core portion, it is a softening point of the amorphous resin (A). The amorphous resin (A) and crystalline polyester or amorphous When an amorphous resin other than the resin (A) is used, a temperature obtained by weighted averaging the softening points of the amorphous resin (A) and the amorphous resin other than the crystalline polyester or the amorphous resin (A) Is the “softening point of the binder resin in the core”. Moreover, when using a masterbatch, the temperature which carried out the weighted average including the resin used for it is made into the softening point of mixed resin.

In addition, additives such as a colorant and a charge control agent may be mixed in advance with a binder resin containing an amorphous resin (A) when preparing resin particles, and each additive may be separately dispersed in water or the like. You may prepare the dispersion liquid disperse | distributed in the medium, mix with the binder resin particle containing an amorphous resin (A), and other resin particles, and use for an aggregation process. When the additive is previously mixed with the binder resin containing the amorphous resin (A) when preparing the resin particles, the binder resin containing the amorphous resin (A) and the additive are previously melt-mixed. It is preferable to smelt.
For melt kneading, it is preferable to use an open roll type biaxial kneader. The open roll type twin-screw kneader is a kneader in which two rolls are arranged close to each other in parallel, and a heating function or a cooling function can be imparted by passing a heat medium through each roll. Therefore, the open roll type twin screw kneader is an open type part to be melt kneaded, and is provided with a heating roll and a cooling roll. The heat of kneading generated can be easily dissipated.

[Distributed processing]
An aqueous dispersion of a binder resin containing an amorphous resin (A), an aqueous dispersion containing an amorphous resin other than the crystalline polyester or the amorphous resin (A) used as necessary, and various additions From the viewpoint of uniformly dispersing the mixture of the agent with the aqueous dispersion, the temperature is preferably lower than the softening point of the core binder resin, more preferably "the softening point of the core binder resin -30 ° C" or less. Disperse treatment at temperature. Specifically, it is preferably 70 ° C. or less, more preferably 65 ° C. or less, and the dispersion treatment should be performed at a temperature higher than 0 ° C. from the viewpoint of fluidity of the medium and production energy of the aqueous dispersion of the resin. Is preferable, and it is more preferable to carry out at 10 degreeC or more.
From these viewpoints, a uniform resin dispersion can be prepared by a usual method such as stirring at a temperature of preferably about 0 to 70 ° C., more preferably about 10 to 65 ° C. for dispersion treatment.

  As a method of dispersion treatment, high-speed stirring such as Ultra Disper (trade name, manufactured by Asada Tekko Co., Ltd.), Ebara Milder (trade name, manufactured by Ebara Corporation), and TK Homomixer (trade name, manufactured by Primix Co., Ltd.) High pressure homogenizer (product name) manufactured by Izumi Food Machinery Co., Ltd., homovalve type high pressure homogenizer represented by Minilab 8.3H type (product name manufactured by Rannie); Microfluidizer (product name manufactured by Microfluidics) ) And Nanomizer (trade name, manufactured by Nanomizer Co., Ltd.) and the like.

[Volume Median Particle Size of Resin Particle I]
The volume median particle size of the resin particles I obtained in Step 1 is preferably 1 to 10 μm, more preferably 2 to 8 μm, and more preferably 3 to 7 μm from the viewpoint of uniformly uniting in the subsequent Step 3 to produce toner particles. Is more preferable.

<Process 2>
Step 2 is a step of obtaining a resin aqueous dispersion containing the amorphous resin (B). The method for obtaining the aqueous dispersion and preferred physical properties are the same as in Step 1 above.

<Step 3>
Step 3 was obtained in Step 2 with the aqueous dispersion of core-forming resin particles I obtained by agglomerating the aqueous dispersion of the binder resin containing the amorphous resin (A) in Step 1 above. In this step, the resin aqueous dispersion containing the amorphous resin (B) is mixed and aggregated to obtain an aqueous dispersion of the resin particles II.
In step 3, the volume median particle size of the resin aqueous dispersion containing the amorphous resin (B) to be mixed is preferably 50 to 1,000 nm, and preferably 50 to 500 nm, from the viewpoint of producing uniform core-shell particles. More preferably, 50-400 nm is still more preferable, and 100-350 nm is still more preferable.
The amorphous resin (B) to be mixed is preferably 5 to 200 parts by weight, more preferably 10 to 100 parts by weight, still more preferably 100 parts by weight of the resin particles I obtained in the step 1. 25 to 60 parts by weight.
The weight ratio of the amorphous resin (A) to the amorphous resin (B) in the resin particles II obtained in step 3 is the same as that of the amorphous resin (A) and the amorphous resin (B). It is as the weight ratio.
The average particle size of the resin particles II obtained in step 3 is preferably 1-10 μm in volume median particle size, more preferably 2-8 μm, from the viewpoint of uniformly uniting in the subsequent step 4 to produce toner particles. 3 to 7 μm is more preferable. Aggregation conditions are the same as in Step 1 described above.

<Step 4>
In Step 4, after adding an aggregation terminator to the aqueous dispersion of resin particles II obtained in Step 3 as necessary, the resultant is subjected to a coalescence step, thereby coalescing the aggregated particles B in the aqueous dispersion. This is a step of obtaining an aqueous dispersion of coalesced particles.
In step 4, the aggregated particles obtained in step 3 can be united by heating.
The temperature in the system in the step 4 is not less than “softening point of the binder resin−50 ° C.” or more and “the softening point + 10” from the viewpoint of the target particle size, particle size distribution, shape control and particle fusing property. "Softening point -45 ° C" or higher, "softening point + 10 ° C" or lower, more preferably "softening point-40 ° C" or higher, and "softening point + 10 ° C" or lower. Specifically, from the same viewpoint, it is preferably maintained at 40 to 90 ° C, more preferably 50 to 80 ° C. The stirring speed is preferably a speed at which the aggregated particles do not settle. Here, the softening point of the binder resin is a temperature obtained by weighted average of the softening point of the amorphous resin (A) and the softening point of the amorphous resin (B), and the crystallinity is obtained. When an amorphous resin other than polyester, amorphous resin (A) and amorphous resin (B) is used, the softening point of amorphous resin (A) and the softening point of amorphous resin (B) The temperature obtained by weighted averaging the softening points of the other resins is referred to as “binder resin softening point”.
In addition, when using a coagulation terminator, it is preferable to use a surfactant as the coagulation terminator, and it is more preferable to use an anionic surfactant from the viewpoint of availability and operability. Of the anionic surfactants, it is more preferable to use at least one selected from the group consisting of alkyl ether sulfates, alkyl sulfates, and linear alkylbenzene sulfonates.

  In the case of using crystalline polyester, from the viewpoint of achieving both low-temperature fixability and storage stability of the toner after coalescence and cooling, further, “melting point of crystalline polyester—10 ° C.” to “melting point of crystalline polyester— It may be raised to a temperature of “30 ° C.” and a temperature of 40 ° C. to “unification temperature −10 ° C.”.

[Electrophotographic toner]
The coalesced particles obtained in the step 4 are appropriately subjected to a solid-liquid separation step such as filtration, a washing step, and a drying step to obtain the electrophotographic toner of the present invention (sometimes simply referred to as a toner). be able to.
In the washing step, an acid may be used to remove metal ions on the toner surface in order to ensure sufficient charging characteristics and reliability as the toner. Further, it is preferable to completely remove the added nonionic surfactant by washing, and washing with an aqueous solution below the cloud point of the nonionic surfactant is preferred. The washing is preferably performed a plurality of times.
In the drying step, any method such as a vibration type fluidized drying method, a spray drying method, a freeze drying method, a flash jet method, or the like can be employed. The water content after drying of the toner is preferably adjusted to 1.5% by weight or less, more preferably 1.0% by weight or less, from the viewpoint of chargeability.

Further, an external additive may be added for the purpose of improving fluidity. Examples of the external additive include silica fine particles whose surface is hydrophobized, titanium oxide fine particles, alumina fine particles, cerium oxide fine particles, and inorganic fine particles such as carbon black; polymer fine particles such as polycarbonate, polymethyl methacrylate, and silicone resin, and the like. Fine particles can be used.
The number average particle diameter of the external additive is preferably 4 to 200 nm, more preferably 8 to 30 nm, from the viewpoint of the fluidity of the toner. The number average particle diameter of the external additive is determined using a scanning electron microscope or a transmission electron microscope.

  In the case of adding an external additive, the amount added is 0.1% relative to 100 parts by weight of the toner before the processing with the external additive, from the viewpoint of the fluidity of the toner, the environmental stability of the charging degree, and the weighted storage stability. 1-5 weight part is preferable, 0.1-1 weight part is more preferable, 0.2-0.8 weight part is still more preferable.

(Physical properties of electrophotographic toner)
The volume median particle size of the electrophotographic toner of the present invention is preferably from 1 to 10 μm, more preferably from 2 to 8 μm, and even more preferably from 3 to 7 μm, from the viewpoints of high image quality and productivity of the toner.
Further, the softening point of the toner is preferably 80 to 160 ° C., more preferably 80 to 150 ° C., and further preferably 90 to 140 ° C. from the viewpoints of low-temperature fixability, charging stability, environmental stability and heat-resistant storage stability of the toner. preferable.
The electrophotographic toner of the present invention can be used as a one-component developer or a two-component developer mixed with a carrier.

About each physical-property value of resin etc., it measured with the following method.
<Softening point of resin>
Using a flow tester (manufactured by Shimadzu Corporation, trade name: “CFT-500D”), a 1 g sample was heated at a heating rate of 6 ° C./min, a load of 1.96 MPa was applied by a plunger, and the diameter was 1 mm. And extruded from a 1 mm long nozzle. The amount of plunger drop of the flow tester was plotted against the temperature, and the temperature at which half of the sample flowed out was taken as the softening point.

<Maximum peak temperature and melting point of endothermic resin>
Using a differential scanning calorimeter (manufactured by TA Instruments Japan, trade name: “Q-100”), a sample cooled from room temperature (20 ° C.) to 0 ° C. at a cooling rate of 10 ° C./min. The measurement was continued for 1 minute as it was, and then the temperature was increased to 180 ° C. at a temperature increase rate of 10 ° C./min. Among the observed endothermic peaks, the temperature of the peak on the highest temperature side is defined as the maximum peak temperature of the endotherm, and if the maximum peak temperature is within 20 ° C. from the softening point, it is defined as the melting point of the crystalline polyester.

<Glass transition temperature of amorphous resin>
Using a differential scanning calorimeter (trade name: “Q-100”, manufactured by TA Instruments Japan Co., Ltd.), 0.01 to 0.02 g of the sample was weighed into an aluminum pan, and the temperature was raised to 200 ° C. Then, the temperature was cooled to 0 ° C. at a rate of temperature decrease of 10 ° C./min. Next, the measurement was performed while increasing the temperature to 150 ° C. at a temperature increase rate of 10 ° C./min. The glass transition temperature was defined as the temperature at the intersection of the base line extension below the maximum peak temperature of endotherm and the tangent indicating the maximum slope from the peak rising portion to the peak apex.

<Resin acid value>
The acid value of the resin was measured based on the method of JIS K 0070. However, only the measurement solvent was changed from the mixed solvent of ethanol and ether specified in JIS K 0070 to a mixed solvent of acetone and toluene (acetone: toluene = 1: 1 (volume ratio)).

<Volume Median Particle Size (D ₅₀ ) of Resin Particles, Colorant Fine Particles, Release Agent Fine Particles, and Charge Control Agent Fine Particles>
Using a laser diffraction particle size analyzer (Horiba, Ltd., trade name: “LA-920”), distilled water is added to the measurement cell, and the volume-median particle size (with a concentration within the appropriate range of absorbance) D ₅₀ ) was measured.

Production Example 1
(Production of alkylene compound A)
Using propylene tetramer (trade name: “Light Tetramer” manufactured by Nippon Oil Corporation), fractionation was carried out under heating conditions of 183 to 208 ° C. to obtain alkylene compound A. The obtained alkylene compound A had 40 peaks in gas chromatography mass spectrometry described later. The distribution of the alkylene compound was as follows: C ₉ H ₁₈ : 0.5 wt%, C ₁₀ H ₂₀ : 4 wt%, C ₁₁ H ₂₂ : 20 wt%, C ₁₂ H ₂₄ : 66 wt%, C ₁₃ H ₂₆ : 9 % By weight and C ₁₄ H ₂₈ : 0.5% by weight.

[Analysis of Alkylene Compound A by Mass Spectrometry Gas Chromatography]
A CI ion source and the following analytical column were attached to a mass spectrometric gas chromatograph (GC / MS) and started up. In addition, CI reaction gas (methane) was flowed, and tuning was performed 24 hours after the evacuation work of the MS part.

(1) GC
Gas chromatograph:
Product name: “HP6890N”, manufactured by Agilent
Analytical column:
Ultra 1 manufactured by HP (trade name, column length 50 m, inner diameter 0.2 mm, film thickness 0.33 μm)
GC oven temperature rising condition:
Initial temperature 100 ° C (0 minutes)
First stage heating rate 1 ° C / min (up to 150 ° C)
Second stage heating rate 10 ° C / min (up to 300 ° C)
Final temperature 300 ° C (10 minutes)
Sample injection volume: 1 μL
Inlet conditions:
Injection mode Split method Split ratio 50: 1
Inlet temperature 300 ° C
Carrier gas:
Gas helium flow rate 1ml / min (constant flow mode)

(2) Detector mass spectrometer: manufactured by Agilent, trade name: “5973N MSD”
Ionization method: Chemical ionization method Reaction gas: Isobutane temperature setting:
Quadrupole 150 ° C
Ion source 250 ℃
Detection condition: Scan scan range: m / z 75-300
Detector ON time: 5 minutes Calibration (mass calibration and sensitivity adjustment):
Reaction gas Methane calibrant PFDTD (Perfluoro-5,8-dimethyl-3,6,9-trioxidedecane)
Tuning method Auto tuning

(3) Sample preparation Propylene tetramer was prepared by dissolving in isopropyl alcohol at a concentration of 5% by weight.

(Data processing method)
For the alkene component of each carbon number in the range of 9 to 14 carbon atoms, a mass chromatogram with a mass number corresponding to each molecular ion is extracted, and under the condition of S / N (signal / noise ratio)> 3, Integration was performed according to the integration conditions for each component shown in Tables 2-5. From the detection results shown in Table 1, the ratio of the specific alkyl chain length component was calculated by the following formula.

(4) Integration condition component: C ₉ H ₁₈

Ingredient: C ₁₀ H ₂₀

Ingredients: C ₁₁ H ₂₂ , C ₁₂ H ₂₄ and C ₁₃ H ₂₆

Ingredients: C ₁₄ H ₂₈

  In the present invention, an alkylene compound having 9 to 14 carbon atoms refers to a peak corresponding to a molecular ion in gas chromatography mass spectrometry.

Production Example 2
(Production of alkenyl succinic anhydride A)
1 L autoclave manufactured by Nitto Koatsu Co., Ltd. 542.4 g of alkylene compound A, 157.2 g of maleic anhydride, 0.4 g of antioxidant Chelex-O (manufactured by SC Organic Chemical Co., Ltd., Triisooctyl phosphite), butyl as a polymerization inhibitor Hydroquinone (0.1 g) was charged and pressurized nitrogen substitution (0.2 MPaG) was repeated three times. After stirring was started at 60 ° C., the temperature was raised to 230 ° C. over 1 hour and the reaction was performed for 6 hours. The pressure when the reaction temperature was reached was 0.3 MPaG. After completion of the reaction, the reaction mixture was cooled to 80 ° C., returned to normal pressure (101.3 kPa), and transferred to a 1 L four-necked flask. The temperature was raised while stirring to 180 ° C., and the remaining alkylene compound was distilled off at 1.3 kPa over 1 hour. Subsequently, after cooling to room temperature (25 ° C.), the pressure was returned to normal pressure (101.3 kPa) to obtain 406.1 g of the target alkenyl succinic anhydride A. The average molecular weight of alkenyl succinic anhydride A determined from the acid value was 268.

Production Examples 3-8
(Production of amorphous resins A1, A2, A4, B1, B3, B7)
Dehydration tube equipped with a fractionation tube through which a raw material monomer of polyester other than trimellitic anhydride shown in Table 6 and Table 7, tin (II) dioctylate salt and gallic acid was passed through a nitrogen introduction tube and hot water at 100 ° C In a 5-liter four-necked flask equipped with a stirrer and a thermocouple, the mixture was kept at 180 ° C. for 1 hour in a nitrogen atmosphere, then heated from 180 ° C. to 230 ° C. at 10 ° C./hour, and then 230 ° C. For 10 hours, and further reacted at 230 ° C. and 8.0 kPa for 1 hour. Further, trimellitic anhydride was reacted at 210 ° C. and reacted at 10 kPa to the desired softening point to obtain amorphous resins A1, A2, A4, B1, B3, and B7.

Production Example 9
(Production of resin c1 (crystalline polyester))
The raw material monomer of polyester shown in Table 6 and tertiary butyl catechol as a polymerization inhibitor were placed in a 5-liter four-necked flask equipped with a nitrogen introduction tube, a dehydration tube, a stirrer, and a thermocouple, and 140 ° C. for 5 hours. Then, the reaction was carried out while increasing the temperature up to 200 ° C. at a rate of 10 ° C./hour. After reacting at 200 ° C. to a reaction rate of 80%, tin (II) dioctylate salt shown in Table 6 was added, and further reacted at 200 ° C. for 2 hours. Furthermore, reaction was performed at 8 kPa for 2 hours, and resin c1 (crystalline polyester) was obtained.

Production Examples 10-13
(Production of amorphous resins A3 and B4-6)
Polyester raw material monomers other than trimellitic anhydride shown in Table 6 and Table 7, dioctylic acid tin (II) salt and gallic acid, 4 liters of 5 liters equipped with nitrogen introduction tube, dehydration tube, stirrer and thermocouple The mixture was placed in a necked flask, subjected to a condensation polymerization reaction at 230 ° C. for 10 hours in a nitrogen atmosphere, and further reacted at 230 ° C. and 8.0 kPa for 1 hour. Furthermore, trimellitic anhydride was reacted at 210 ° C. and reacted to a desired softening point at 10 kPa to obtain amorphous resins A3 and B4 to 6.

Production Example 14
(Production of amorphous resin B2)
Dehydration tube equipped with a fractionation tube through which nitrogen monomer, 100 ° C hot water was passed through raw material monomers of polyester other than trimellitic anhydride and fumaric acid shown in Table 7, tin (II) dioctylate and gallic acid In a 5-liter four-necked flask equipped with a stirrer and a thermocouple, the mixture was kept at 180 ° C. for 1 hour in a nitrogen atmosphere, then heated from 180 ° C. to 230 ° C. at 10 ° C./hour, and then 230 ° C. For 10 hours, and further reacted at 230 ° C. and 8.0 kPa for 1 hour. After cooling to 180 ° C., trimellitic anhydride, fumaric acid and tertiary butyl catechol as a polymerization inhibitor were added, the temperature was raised from 180 ° C. to 210 ° C. at 10 ° C./hr, and the reaction was carried out at 210 ° C. for 1 hour. The reaction was carried out at 210 ° C. and 10 kPa until the softening point reached 103.9 ° C. to obtain an amorphous resin B2.

Production Examples 15 to 26
(Preparation of resin particle dispersion)
Amorphous resins A1 to A4 and crystalline polyester produced in Production Examples 3 to 12 above were charged in 600 g of methyl ethyl ketone in a 5 L container equipped with a stirrer, reflux condenser, dropping funnel, thermometer and nitrogen inlet tube. About each of c1 and amorphous resin B1-B7, 200g was added at 60 degreeC, and it was made to melt | dissolve. 4 g of sodium hydroxide was added to each of the obtained solutions for neutralization, followed by addition of 2000 g of ion-exchanged water, and then methyl ethyl ketone was distilled at a temperature of 50 ° C. or lower under reduced pressure at a stirring rate of 250 r / min. To obtain a self-dispersing aqueous resin particle dispersion (resin content: 9.6% by weight (in terms of solid content)). The volume median particle size of the resin particles dispersed in the obtained resin particle dispersion was about 0.3 μm.

Production Example 27
(Preparation of colorant dispersion)
50 g of copper phthalocyanine (manufactured by Dainichi Seika Kogyo Co., Ltd., model number: “ECB-301”), 5 g of nonionic surfactant (trade name: “Emulgen 150”, manufactured by Kao Corporation) and 200 g of ion-exchanged water are mixed. A colorant dispersion was obtained by dispersing for 10 minutes at 25 ° C. using a homogenizer. The volume median particle size was 120 nm.

Production Example 28
(Preparation of release agent dispersion)
50 g of paraffin wax (manufactured by Nippon Seiwa Co., Ltd., trade name: “HNP0190”, melting point: 85 ° C.), 5 g of cationic surfactant (trade name: “Sanisol B50”, manufactured by Kao Corporation) and 200 g of ion-exchanged water The mixture was heated to 95 ° C., and the paraffin wax was dispersed using a homogenizer, followed by dispersion treatment using a pressure discharge homogenizer to obtain a release agent dispersion. The volume median particle size of the release agent was 550 nm.

Production Example 29
(Preparation of charge control agent dispersion)
50 g of charge control agent (Orient Chemical Industries, Ltd., salicylic acid compound, trade name: “Bontron E-84”), 5 g of nonionic surfactant (trade name: “Emulgen 150”, manufactured by Kao Corporation) and ion exchange 200 g of water was mixed and dispersed at 10C using glass beads for 10 minutes using a sand grinder to obtain a charge control agent dispersion. The volume median particle size of the charge control agent was 500 nm.

Examples 1-11 and Comparative Examples 1-2
(Manufacture of dispersion of core-shell resin particles and toner)
500 g of the core resin dispersion, 20 g of the colorant dispersion, 5 g of the release agent dispersion, 4 g of the charge control agent dispersion, and a cationic surfactant (trade name: “SANISOL B50, manufactured by Kao Corporation) of combinations shown in Table 8. ] 1.5g was mixed and disperse | distributed using the homogenizer in the round stainless steel flask, and it heated to 48 degreeC, stirring the inside of a flask in the oil bath for heating. Furthermore, it hold | maintained at 48 degreeC for 1 hour, and the aggregated particle was formed. The volume median average particle size of the aggregated particles at this time was 5.1 μm. Thereafter, 150 g (Examples 1 to 7, Examples 9 to 11 and Comparative Examples 1 to 2) or 300 g (Example 8) of the shell resin dispersion shown in Table 8 was added, and the mixture was stirred and dispersed to encapsulate. Agglomerated particles that were core-shell particles were obtained.
After adding 3 g of an anionic surfactant (trade name: “Perex SS-L”, manufactured by Kao Corporation) to the aggregated particle dispersion in which the core-shell aggregated particles are formed, a reflux tube is attached to the stainless steel flask. While stirring, the mixture was heated to 75 ° C. at a rate of 0.1 ° C./min and held for 2 hours to coalesce and fuse the aggregated particles. Thereafter, the mixture was cooled, the fused particles were filtered, sufficiently washed with ion exchange water, and then dried to obtain colored resin fine particle powder. All of the resulting colored resin fine particle powders had a volume-median particle size (D ₅₀ ) of 5.0 μm.
0.5 parts by weight of an external additive (hydrophobic silica, manufactured by Nippon Aerosil Co., Ltd., trade name: “Aerosil R-972”, number average particle diameter: 16 nm) is added to 100 parts by weight of the colored resin fine particles. Mixing for 5 minutes at 3600 r / min (peripheral speed 31.7 m / s) with a mixer (manufactured by Mitsui Mining Co., Ltd., current Nippon Coke Kogyo Co., Ltd.), toner particles (in volume) A toner having a unit particle size D ₅₀ = 5.0 μm was obtained.

[Evaluation]
(Low temperature fixability)
Toner was mounted on a copier (manufactured by Sharp Corporation, trade name: “AR-505”), and printed on a fixing paper for evaluation. Before passing through the fixing machine, a solid image was taken out to obtain an unfixed image (printing area: 2 cm × 12 cm, adhesion amount: 0.5 mg / cm ² ). The obtained paper having an unfixed image is loaded into a copying machine (trade name: “AR-505”, manufactured by Sharp Corporation), and a solid image is taken out before passing through the fixing device twice. Printing was performed to obtain an unfixed image (three layers) having a layer thickness of 1.5 mg / cm ² .
The obtained three-layer unfixed image was fixed on a sheet at 300 mm / second while the fixing device of the copying machine was offline and the fixing temperature was sequentially increased from 90 ° C. to 240 ° C. in 5 ° C. increments. In addition, as the fixing paper for evaluation, fixing standard paper (manufactured by Sharp Corporation, trade name: “CopyBond SF-70NA”, 75 g / m ² ) was used.
A sand eraser with a bottom of 15 mm × 7.5 mm with a load of 500 g is applied, and the image fixed through the fixing machine is rubbed 5 times, and the optical reflection density before and after rubbing is measured by a reflection densitometer (manufactured by Macbeth, trade name: “RD-915”), and the fixing roller temperature at which the ratio between the two (after rubbing / before rubbing) first exceeded 80% was defined as the minimum fixing temperature. The lower the minimum fixing temperature, the better the low-temperature fixing property. The results are shown in Table 8.

Since Comparative Examples 1 and 2 do not use alkenyl succinic anhydride as the carboxylic acid component of the shell portion, the low-temperature fixability is insufficient.
On the other hand, in Examples 1-11, since alkenyl succinic anhydride is used as a carboxylic acid component of a shell part, it is excellent in low temperature fixability.
When Examples 1-3, 6-7, 9-11 and Examples 4-5 are compared, Examples 1-3, 6-7, 9-11 which use aliphatic alcohol as an alcohol ingredient of a shell part are compared. Is superior to Examples 4 to 5 using bisphenol A in terms of low-temperature fixability.
When Example 1 (resin mixing ratio: 100/30) and Example 8 (resin mixing ratio: 100/60) are compared, Example 1 having a lower shell ratio has a lower temperature fixability. Are better.

(Charge stability under high temperature and high humidity)
Under a high temperature and high humidity condition of a temperature of 32 ° C. and a relative humidity of 85%, 0.6 g of toner and 19.4 g of a silicone ferrite carrier (manufactured by Kanto Denka Kogyo Co., Ltd., average particle size 90 μm) are placed in a 50 ml polybin. The toner was mixed at 250 r / min using a ball mill, and the charge amount of the toner was measured using a Q / M meter (manufactured by EPPING) by the following method.
After a predetermined mixing time, a specified amount of toner / carrier mixture is put into a cell attached to the Q / M meter, and only the toner is passed through a sieve having a mesh size of 32 μm (stainless steel, twill, wire diameter: 0.0033 mm) for 90 seconds. Aspirated. The change in voltage on the carrier generated at that time was monitored, and the value of [total amount of electricity after 90 seconds (μC) / amount of attracted toner (g)] was defined as the charge amount (μC / g). The ratio between the charge amount after 60 seconds of mixing time and the charge amount after 600 seconds of mixing time (charge amount after 60 seconds of mixing time / charge amount after 600 seconds of mixing time) was calculated to evaluate the charging stability. The larger the value, the better the charging stability under high temperature and high humidity. The charging stability was evaluated according to the following evaluation criteria. The results are shown in Table 8.
In Comparative Examples 1 and 2, since alkenyl succinic anhydride is not used as the carboxylic acid component of the shell portion, the charging stability is insufficient. Further, Comparative Example 2 in which bisphenol A is not used as the alcohol component of the core part is inferior in charging stability to Comparative Example 1 in which an alkylene oxide adduct of bisphenol A is used as the alcohol component of the core part.
On the other hand, in Examples 1-11, since alkenyl succinic anhydride is used as a carboxylic acid component of a shell part, it is excellent in charging stability.
When Examples 1 to 3 are compared, the charging stability is better as the content of alkenyl succinic anhydride in the shell portion is larger.
When Example 4 is compared with Examples 1 to 3, Examples 1 to 3 using an aliphatic alcohol as the alcohol component of the shell are more excellent in charging stability.
When Example 5 is compared with Example 1, Example 1 has a lower content of alkenyl succinic anhydride in the shell portion, but uses an aliphatic alcohol as the alcohol component in the shell portion. Is more excellent in charging stability.
When Example 7 is compared with Example 1, Example 1 in which the crystalline polyester is not contained in the core part is superior in charging stability.

  Since the toner of the present invention has characteristics such as excellent low-temperature fixability and charging stability, it can be suitably used as an electrophotographic toner used in electrophotography, electrostatic recording method, electrostatic printing method and the like.

Claims (5)

  The core portion includes an amorphous resin (A) obtained by polycondensing an alcohol component containing an aliphatic diol having 2 to 6 carbon atoms and a carboxylic acid component not containing alkenyl succinic acid, and the shell portion is An electrophotographic toner comprising core-shell particles as a binder resin, which is an amorphous resin (B) obtained by condensation polymerization of an alcohol component and a carboxylic acid component containing alkenyl succinic acid.   The toner for electrophotography according to claim 1, wherein the content of alkenyl succinic acid in the carboxylic acid component of the amorphous resin (B) is 5 mol% or more.   The electrophotographic toner according to claim 1, wherein the alcohol component of the amorphous resin (B) contains an aliphatic diol having 2 to 6 carbon atoms.   The toner for electrophotography according to claim 1, wherein the core portion does not contain crystalline polyester. A method for producing an electrophotographic toner, comprising the following steps 1 to 4.
Step 1: Aggregating an aqueous resin dispersion containing an amorphous resin (A) obtained by condensation polymerization of an alcohol component containing an aliphatic diol having 2 to 6 carbon atoms and a carboxylic acid component not containing alkenyl succinic acid To obtain an aqueous dispersion of resin particles I Step 2: A resin aqueous dispersion containing an amorphous resin (B) obtained by condensation polymerization of an alcohol component and a carboxylic acid component containing alkenyl succinic acid Step 3: The aqueous dispersion of resin particles I obtained in Step 1 and the aqueous resin dispersion containing the amorphous resin (B) obtained in Step 2 are mixed and agglomerated to form resin particles II. Step of obtaining aqueous dispersion Step 4: Step of uniting resin particles II obtained in Step 3